This application claims the benefit of the Korean Application No. P2002-32899 filed on Jun. 12, 2002, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a multi-unit air conditioner, and a method for controlling the same.
2. Background of the Related Art
In general, the air conditioner is an appliance for cooling or heating spaces, such as living spaces, restaurants, and offices. At present, for effective cooling or heating of a space partitioned into many rooms, there have been ceaseless developments of multi-unit air conditioners. The multi-unit air conditioner is in general provided with one outdoor unit and a plurality of indoor units each connected to the outdoor unit and installed in a room, for cooling or heating the room while operating in either a cooling or heating mode.
However, since the multi-unit air conditioner is operable only either in the cooling or heating mode uniformly even if some of the rooms within the partitioned space require heating, and rest of the rooms require cooling, the multi-unit air conditioner has a limit in that the requirement can not be met, properly.
For an example, even in a building, there are rooms having a temperature difference depending on locations of the rooms or time of the day, such that while a north side room of the building requires heating, a south side room of the building requires cooling due to the sun light, which can not be dealt with a related art multi-unit air conditioner that is only operable in a single mode.
Moreover, even though a building equipped with a computer room requires cooling not only in summer, but also in winter for solving the problem of heat load from the computer related equipment, the related art multi-unit air conditioner can not deal with such a requirement, properly.
In conclusion, the requirement demands development of a multi-unit air conditioner and a method for controlling the same that can air condition rooms individually, i.e., the indoor unit installed in a room requiring heating is operable in a heating mode, and, at the same time, the indoor unit installed in a room requiring cooling is operable in a cooling mode.
Accordingly, the present invention is directed to a multi-unit air conditioner and a method for controlling the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a multi-unit air conditioner and a method for controlling the same which can carry out cooling operation and heating operation at the same time.
Another object of the present invention is to provide a multi-unit air conditioner and a method for controlling the same, in which a piping system connecting a distributor and indoor units are simplified, to easy piping work in installation of the indoor units and improving outer appearance.
Further object of the present invention is to provide a multi-unit air conditioner and a method for controlling the same, in which a mixing ratio of refrigerant introduced into a gas-liquid separator is optimized for different operation conditions for improving an air conditioning efficiency of the multi-unit air conditioner.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, the multi-unit air conditioner includes an outdoor unit including an accumulator, a plurality of compressors and outdoor heat exchangers connected with an outdoor unit piping system, plurality of outdoor fans for respectively cooling the outdoor heat exchangers, a four way valve and a plurality of control valves mounted on the outdoor unit piping system for controlling refrigerant flow, a plurality of indoor units respectively installed in rooms each having an indoor heat exchanger and an electronic expansion valve, a distributor including a gas-liquid separator for separating refrigerant received from the outdoor unit into gas refrigerant and liquid refrigerant, or mixing refrigerant received from the indoor units, and a distribution piping system for guiding the refrigerant from the outdoor unit toward the indoor units and the refrigerant from the indoor units to the outdoor unit again, and control means for controlling rotation speeds of the outdoor fans, to control a gas/liquid refrigerant mixing ratio introduced into the gas-liquid separator through the outdoor heat exchangers.
The outdoor heat exchanger includes a first outdoor heat exchanger for discharging liquid refrigerant proper to an operation condition, and a second outdoor heat exchanger for discharging two phased refrigerant proper to the operation condition.
The outdoor fan includes a first outdoor fan for condensing refrigerant at the first outdoor heat exchanger, and a second outdoor fan for condensing refrigerant at the second outdoor heat exchanger.
The control means includes a temperature sensor for measuring a temperature of refrigerant introduced from the outdoor heat exchangers into the gas-liquid separator, and a microcomputer for comparing a refrigerant temperature measured with the temperature sensor and a preset refrigerant temperature, to detect a refrigerant mixing ratio at the outdoor unit piping system, and controlling rotation speeds of the outdoor fans so that detected refrigerant mixing ratios are the same with refrigerant mixing ratios preset to be proper to operation conditions, respectively. The refrigerant is R407C mix refrigerant of which refrigerant mixing ratio can be known accurately according to a temperature variation.
The outdoor unit piping system includes a first pipeline connected between outlets of the compressors and the four way valve, a second pipeline branched into two pipeline in front of the first and second outdoor heat exchangers, and connected between the four way valve and the first and second outdoor heat exchangers in parallel, a third pipeline joined in front of the gas-liquid separator, and connected between the gas-liquid separator and the outdoor heat exchangers in parallel, a fourth pipeline connected between the distribution piping system and the four way valve, a fifth pipeline connected between the four way valve and the accumulator, and a sixth pipeline connected between the accumulator and an inlet of the compressor.
The outdoor heat exchangers include a first outdoor heat exchanger for discharging liquid refrigerant proper to an operation condition, and a second outdoor heat exchanger for discharging two phased refrigerant proper to the operation condition. The outdoor fans include a first outdoor fan for condensing refrigerant at the first outdoor heat exchanger, and a second outdoor fan for condensing refrigerant at the second outdoor heat exchanger.
The control means includes a temperature sensor provided at a part the third pipeline joins for measuring a temperature of refrigerant introduced from the first and second outdoor heat exchangers into the gas-liquid separator, and a microcomputer for comparing a refrigerant temperature measured with the temperature sensor and a preset refrigerant temperature, to detect a refrigerant mixing ratio at the outdoor unit piping system, and controlling a rotation speed of the second outdoor fan so that detected refrigerant mixing ratios are the same with refrigerant mixing ratios preset to be proper to operation conditions, respectively.
The control valve includes first, and second check valves provided on sides of the first, and second outdoor heat exchangers of the third pipeline for controlling a refrigerant flow from the first and second outdoor heat exchangers to the gas-liquid separator, and first and second electronic expansion valves provided in parallel with the first and second check valves for expanding refrigerant flowing from the gas-liquid separator to the first and second outdoor heat exchangers.
The distribution piping system includes a liquid refrigerant pipeline connected to the gas-liquid separator for guiding liquid refrigerant to/from the gas-liquid separator, liquid refrigerant branch pipelines branched from the liquid refrigerant pipeline, and connected to the indoor heat exchangers respectively, a gas refrigerant pipeline connected to the gas-liquid separator for guiding gas refrigerant to/from the gas-liquid separator, gas refrigerant branch pipelines branched from the gas refrigerant pipeline and connected to the indoor heat exchangers, respectively, and intermediate branch pipelines respectively branched from the gas refrigerant branch pipelines, and connected to the outdoor unit piping system.
The gas refrigerant branch pipelines and the liquid refrigerant branch pipelines are arranged in parallel to each other for piping work efficiency. The outdoor heat exchanger includes a first outdoor heat exchanger for discharging liquid refrigerant proper to an operation condition, and a second outdoor heat exchanger for discharging two phased refrigerant proper to the operation condition. The outdoor fans include a first outdoor fan for condensing refrigerant at the first outdoor heat exchanger, and a second outdoor fan for condensing refrigerant at the second outdoor heat exchanger.
The outdoor unit piping system includes a first pipeline connected between outlets of the compressors and the four way valve, a second pipeline branched into two pipeline in front of the first and second outdoor heat exchangers, and connected between the four way valve and the first and second outdoor heat exchangers in parallel, a third pipeline joined in front of the gas-liquid separator, and connected between the gas-liquid separator and the first and second outdoor heat exchangers in parallel, a fourth pipeline connected between the intermediate branch pipelines and the four way valve, a fifth pipeline connected between the four way valve and the accumulator, and a sixth pipeline connected between the accumulator and the inlet of the compressor.
The control means includes a temperature sensor provided at a part the third pipeline joins for measuring a temperature of refrigerant introduced from the first and second outdoor heat exchangers into the gas-liquid separator, and a microcomputer for comparing a refrigerant temperature measured with the temperature sensor and a preset refrigerant temperature, to detect a refrigerant mixing ratio at the outdoor unit piping system, and controlling a rotation speed of the second outdoor fan so that detected refrigerant mixing ratios are the same with refrigerant mixing ratios preset to be proper to operation conditions, respectively.
The control valve includes first, and second check valves provided on sides of the first, and second outdoor heat exchangers of the third pipeline for controlling a refrigerant flow from the first and second outdoor heat exchangers to the gas-liquid separator, and first and second electronic expansion valves provided in parallel with the first and second check valves for expanding refrigerant flowing from the gas-liquid separator to the first and second outdoor heat exchangers.
The distributor includes a valve unit for controlling refrigerant flow in the distribution piping system. The valve unit includes two way valves provided on the gas refrigerant branch pipelines, the liquid refrigerant branch pipelines, and intermediate branch pipelines for being turned on/off selectively depending on operation conditions.
In another aspect of the present invention, there is provided a method for operating a multi-unit air conditioner, including the steps of measuring a temperature of refrigerant introduced into a gas-liquid separator through an outdoor unit piping system from a plurality of outdoor heat exchangers with a temperature sensor, comparing a measured refrigerant temperature and a preset refrigerant temperature, to detect a refrigerant mixing ratio flowing through the outdoor unit piping system, and controlling rotation speeds of a plurality of outdoor fans for cooling the outdoor heat exchangers, so that the detected mixing ratio becomes the same with a mixing ratio set proper to an operation condition.
It is to be understood that both the foregoing description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention claimed.